im going to the track in a few days and i figured that i would end the battle once and forall about the resistor tricking the ecm..gaining power myth, well see if it works or not?, you know what im talking about when i say resistor right?, i just heard that you plug it into the airtemp sensor plug and vollia., i have a 1988 fiero formula, 2.8 auto, several mods, nothing serious, i resintly installed the fiero store underdrive pully set, so im wanting to see if that did any thing over my previous 16.4 1/4 mile time, people claim miricles out of the underdrive pullys, but i honestly didnt notice much, we shall see tho.

so what ohm rating (or however there measured) is the one im looking for. resister wise.

and what are sideefects of keeping the resistor in...im thinking bad mpg, have been told that eng will knock after awhile, i can use all the tips and trick i can get here. thanks guys

The one on ebay is 30 OHMS http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&category=33597&item=7987465013

ive been looking at the ebay items..didnt see the one you found, but so basically there selling a 30 ohm resistor for 10$? rip off lol, so can i go to radio shack and get one? all info and opions needed..thanks!

Theres people selling 2$ worth of fastners,clips,ect. for 15$ + shipping. Was not sug. buying it like you said if you want to experiment radio shack for a few cents. Running rich like that will wash oil off cylinder walls accelerating wear,one of the many drawbacks of using on street vehicle. post your results.

Go ahead and try it, but here's what I expect will happen...

-Resistor tricks ECM into thinking it's cold, so it richens up mixture.
-O₂ sensor notices rich mixture and leans it back to where it should be.

Net result: no change.

Using a resistor to give the ECM false information will reduce power, gas mileage, and efficiency. The ECM has to know the correct air temperature because temperature is used to determine air density, a critical part of the fuel calculations.

JazzMan

I used a 10 OHM when I was playing with it. I think when the engine gets hot, then the ecm temp sensor takes over and controls the fuel.. I could tell a little difference when cold but after it got hot I could notice any difference.

Don

Hey, I heard that if you take a 1 Ohm 50 watt resistor and connect it across the big red wire coming from the battery, to frame ground, that it "conditions power" by shunting voltage spikes to ground and the ECM operates more smoothly because there's less RFI and noise. This is said to result in 5-7 HP due to increased ECM efficiency. Why don't you give it a shot....?

Disclaimer: I am in no way responsible if you really do this. At all.

i am in possition of a 2 ohm resistor, i tore apart, radios, clocks, r/c cars, vcr's (all were junk anyway) and the bigest resistor i found was a 2 ohm. some little miniture ones said to be 290ohms, but i dont believe that is posble.(i used ohm chart on comp), and if you run a resistor from the batt hot to the frame it will cause it to ground out resulting in burning the lil resistor in half, which equils no change in jack? right?, im knida doubting that radio shack will have a 30 ohm resistor but will see... so whats the increments of ohms vs temp, for ex: (just a guess) a 30ohm resistor will tell the ecm that out side air is 20*F, so would a 10ohm tell the ecm that the air temp is like 60+*F or will it tell it -20*F and so on??? , basically what im getting at is it posible to trick the comp into beliving that air temps are like -2 million degreese by using right resistor??? this could get interesting....

1 ohm across the battery? Personally I wouldn't do that.

Let's see 14V/1ohm = 14A. 14A x 14V = 196W

50W resistor is a tad small.....

You need to listen for the sarcasm.

quote Originally posted by 88 forumla: what im getting at is it posible to trick the comp into beliving that air temps are like -2 million degreese by using right resistor??? .

Open, it'll read -40
1 ohm, it'll read (250?). Somewhere around there anyhow.

Temperature and resistance are inverse proportional.

quote Originally posted by TK: 1 ohm across the battery? Personally I wouldn't do that. Let's see 14V/1ohm = 14A. 14A x 14V = 196W 50W resistor is a tad small.....

It's only overloaded 4 times over - no biggie, it's a block heater. I was originally going to suggest using an inductor with a really high (AC) impedance (ohm) value, but it would have confused him more possibly spelling needless disassembly of even more electronic goods. Anyways joking aside, 88 Forumla - Please, take the VCR out of your engine compartment and walk away. You're going to wreck your motor or end up humiliating yourself on the track even more at very least. Install a cam or port your exhaust manifolds or something.

quote Originally posted by ka4nkf: I used a 10 OHM when I was playing with it. I think when the engine gets hot, then the ecm temp sensor takes over and controls the fuel.. I could tell a little difference when cold but after it got hot I could notice any difference. Don

The ECM always uses the air temperature sensor readings, no matter how cold it is, or how hot it is for that matter.

JazzMan

The closer the resistance gets to 1 at the air temp harness sensor plug the more the signal indicates hot air (less dense). If you can get a hold of a genuine GM shop manual at least the HELMS company bumper to bumper version it will tell what the resistance reading is for the temperature increments. I used to do this on my camaro engine temp sensor to make the cooling fan come on earlier by tying a cheap radio shack resistor in parallel to bias the resistance towards the low side. I think the formula I used to choose the resistor I needed was:

1/R=1/R1 +1/R2 to get the final resistance reading I would have at the resistance reading the computer was programmed to turn the fan on so that I would know how much sooner it would do so. Not exactly sure what if any affect it had on engine management in regards to the air temp sensor, and as someone said earlier the computer will read the O2 sensor and likely compensate for it. Not sure which of the two sensors the computer gives priority to but I would think it would be the O2 sensor.

Actually, if you want to tell the ECM that the air temp is cold (-40), the chart in the Fiero factory service manual says the equivalent resistance would be 100,700 ohms. Just unplug it and see what it does. If you use low resistance, (185 ohms or lower) you are going to be telling the ECM that the air temp is 210 degrees or higher. This "cheap" mod will probably work about as well as your underdrive pulley. As others here have said, trying to "fool" the ECM generally doesn't work too well.

------------------
Tim
Red 88 Formula Auto 2.8 100K+ Miles

I don't care how much money you have, free stuff is always a good thing.

My understanding is you can always run the motor in diagnostic mode as it disables engine management and runs in a default mode - so it doesn't care what the sensors are reading

[This message has been edited by Mickey_Moose (edited 07-24-2005).]

Ok, folks here is all it takes. First off all you need to do is run down to the local Radio Shack or electronics store and pick up a 100 Kohms +/-5% resister , color bands on resister are Brown, Black, Yellow and Gold. You can calculate all you like but this is what works with the 2.8.
I have not heard of anyone using a 30 K resistor .

Or you can get them here, http://perform.kmd-innovations.com
his Email is mdameron2000@yahoo.com, you may want to Email him and talk to him about what you are trying to accomplish and what motor you have before trying it at all. It is not something I would recommend.... especially not for long term.

pull the sensor wire plug from the sensor . Bend the resistor in a U shape. Place one leg (wire) of the resistor into one of the
holes on the sensor plug and then the other leg (wire) of the resistor into the other hole on the sensor plug.
Thats it. Leave the plug disconnected and maybe cover the resistor and plug with a little electrical tape to keep it from possibly falling out and keep the elements off it. You should disconnect the battery while hooking the resistor up, reconnect it once you are finished.
Your CHECK ENGINE light may or may not come on.

[This message has been edited by Zoom88 (edited 07-24-2005).]

quote Originally posted by Formula88: Go ahead and try it, but here's what I expect will happen... -Resistor tricks ECM into thinking it's cold, so it richens up mixture. -O2 sensor notices rich mixture and leans it back to where it should be. Net result: no change.

Actually it advances your timing. The resistor tricks the ECM into thinking it is the middle of winter in northern Canada. At very cold air temps gasoline doesn't atomize as easily. So the ECM advances the timing to give the air/fuel mix a little more time to "warm-up". The problem with tricking it is it doesn't add fuel so you will start running leaner and hotter. On newer cars they have a knock sensor and if the engine starts running leaner/hotter and knocking the ECM will retard timing to stop the knock. (hence you get no gain.)

Fiero's don't have a knock sensor. So timing advances, engine gets hot, starts knocking, then you start damaging your engine. The O2 sensor will report a lean condition, but the ECM cannot supply enough fuel at WOT to compensate for the higher timing advance.

The ones on Ebay are A) A huge rip-off and B) Can hurt the engine in cars equipped without a knock sensor.

quote Originally posted by FrugalFiero: Actually, if you want to tell the ECM that the air temp is cold (-40), the chart in the Fiero factory service manual says the equivalent resistance would be 100,700 ohms. Just unplug it and see what it does. If you use low resistance, (185 ohms or lower) you are going to be telling the ECM that the air temp is 210 degrees or higher. This "cheap" mod will probably work about as well as your underdrive pulley. As others here have said, trying to "fool" the ECM generally doesn't work too well.

I thought about that later, 2 months ago I checked mine around 5 - 6 hundred OHMS dont remember checked manual said about 80° which is what it was. When I saw 30 OHMS in ad thought I must have remembered wrong and it was temp down res. down, but your right to trick it cold would be way up there in the 100ks. All the more reason not to mess with such things sure GM knows more than any of us

[This message has been edited by Sullivan (edited 07-24-2005).]

I've watched on the wideband what a falty one of those sensors can do to the ECM, (and to use as we had a heck of time trying to figure out why we had such an erratic idle) so instead of tricking it, check the impedence of it and make sure it's spot-on.
BTW: speaking of resistors, I had to ask for one of these at an electronics store one day, try saying this one a few times quick; one ohm, one watt, wire wound resistor. Yes, I ask for a wesisitor. Good luck at the track.

so whats the verdict, im hearing different things, i have a few new questions tho, about the "open", if i disconect the plug and dont put any thing in it what will the ecm think the temp is?, and this 100 Kohms +/-5% resister , color bands on resister are Brown, Black, Yellow and Gold. sounds kinda trusting, so im going to pick up one of thoes to try it out, im only keeping this for a few races, no way long term!, just a test or 2.

btw, last time i was at the track i got better times by letting the trans shift its self, when i held out the gears it hurt my times, which to me doesnt make a bit of sence.

If you were to disconnect the sensor, I'd expect the ECM to realize it's not getting a signal and set a code for a faulty sensor.

The answer is that tricking any of the sensors will not give you any better performance.

------------------
87GT 3.4 Turbo- 0-60 5.2 seconds -Best
Engine Controls, ECM goodies, Chip
re-programming & odd electronics stuff

quote Originally posted by Formula88: If you were to disconnect the sensor, I'd expect the ECM to realize it's not getting a signal and set a code for a faulty sensor.

Yeah, I forgot to add that it would give you a code 23 if you just unhook it.

------------------
Tim
Red 88 Formula Auto 2.8 100K+ Miles

I don't care how much money you have, free stuff is always a good thing.

quote Originally posted by 88 forumla: so whats the verdict, im hearing different things, i have a few new questions tho, about the "open", if i disconect the plug and dont put any thing in it what will the ecm think the temp is?, and this 100 Kohms +/-5% resister , color bands on resister are Brown, Black, Yellow and Gold. sounds kinda trusting, so im going to pick up one of thoes to try it out, im only keeping this for a few races, no way long term!, just a test or 2. btw, last time i was at the track i got better times by letting the trans shift its self, when i held out the gears it hurt my times, which to me doesnt make a bit of sence.

Hey I'm not going to give you any slack over it, like you said its just for a good time at the track. Give it a shot and see what you think.
Only real way to settle this would be on a dyno anyway. Go have some fun !!

ok ive picked up .. a 30ohm resister, a 100kohms, and a 25kohms resistor, will try all of them and run times with nothing done to see difference, yes a dyno would be more acurate, but i have an auto trans, all of my times are withen a 100th of a second, so its pretty reliable i think. will see., il be leaving in about 2 hours, hopefully i can report back tonight. (its soposed to rain) so if that happens then il be extremly pissed off!!

well my last run was a 16.4, since then ive added underdrive pullys, and about 20 bottles of fuel injector cleaner (im talking 2 bottles to rvery 5 gallons of gas!, i get it for "free" and it the good 20gal treat ment stuff. every 4 month..so il see if super duper clean injection/intake system helps too, il be running stright 87 octane, no aditives.

quote Originally posted by 88 forumla: ok ive picked up .. a 30ohm resister, a 100kohms, and a 25kohms resistor, will try all of them and run times with nothing done to see difference, yes a dyno would be more acurate, but i have an auto trans, all of my times are withen a 100th of a second, so its pretty reliable i think. will see., il be leaving in about 2 hours, hopefully i can report back tonight. (its soposed to rain) so if that happens then il be extremly pissed off!! well my last run was a 16.4, since then ive added underdrive pullys, and about 20 bottles of fuel injector cleaner (im talking 2 bottles to rvery 5 gallons of gas!, i get it for "free" and it the good 20gal treat ment stuff. every 4 month..so il see if super duper clean injection/intake system helps too, il be running stright 87 octane, no aditives.

You're doing all this other stuff to shave off a few 10ths and you're still gonna run 87 octane and no additives? Fill it with Premium and throw in a bottle of octane booster. If you're this concerned about bringing your time down, theres no reason not to.

quote Originally posted by 88 forumla: ok ive picked up .. a 30ohm resister, a 100kohms, and a 25kohms resistor, will try all of them and run times with nothing done to see difference, yes a dyno would be more acurate, but i have an auto trans, all of my times are withen a 100th of a second, so its pretty reliable i think. will see., il be leaving in about 2 hours, hopefully i can report back tonight. (its soposed to rain) so if that happens then il be extremly pissed off!! .

There really isn't much of a battle about how what the resistor trick does. People don't waste their time with it because they don't want to cause problems with their motor. On a basically stock motor such as yours, the fiero ECM will run things pretty much optimally if it's getting real signals from the sensors, not fake signals.

If you've added an underdrive pulley your time should be decreased somewhat, but not much. I personally don't think the resistors will make much of a difference. The auto tranny will keep your times more consistent than a manual would, but it's supposed to rain like hell this afternoon so more than likely you'll be dealing with a wet track and traction will be a problem.

One good thing about the rain is you'll get more runs at IRP...less people will come.

Dude, ease up on the injector cleaner. Some of that stuff can clean the insulation right off your injectors and ruin them - especially at the concentrations you're running!!

quote Originally posted by Formula88: Dude, ease up on the injector cleaner. Some of that stuff can clean the insulation right off your injectors and ruin them - especially at the concentrations you're running!!

Not to mention causing fuel pump, fuel line and regulator seals to possibly fail/leak.

quote Originally posted by 88 forumla: ok ive picked up .. a 30ohm resister, a 100kohms, and a 25kohms resistor, will try all of them and run times with nothing done to see difference, yes a dyno would be more acurate, but i have an auto trans, all of my times are withen a 100th of a second, so its pretty reliable i think. will see., il be leaving in about 2 hours, hopefully i can report back tonight. (its soposed to rain) so if that happens then il be extremly pissed off!! well my last run was a 16.4, since then ive added underdrive pullys, and about 20 bottles of fuel injector cleaner (im talking 2 bottles to rvery 5 gallons of gas!, i get it for "free" and it the good 20gal treat ment stuff. every 4 month..so il see if super duper clean injection/intake system helps too, il be running stright 87 octane, no aditives.

Holy s___, dude! You're flooding that engine with injector cleaner. As people have said already, you're fixing to strip the insulation off of your injector windings (which will kill them, possibly doing damage to the the drivers in the ECM too), and screw up a lot of other stuff too. Running your car on a half and half mixture of gas and injector cleaner isn't going to do anything for you than wreck stuff.

Look, not to belittle your motivation or anything, but it looks like you're going to do more harm than good. If you want any performance, do it right. Pull the engine out, port your manifolds, install a cam, stick a Truelo intake on there. Little 10 cent tricks never have and never will work. 10 cent tricks do one thing very well though - costing you a 2000 dollar engine rebuild, which I'm sure you don't want to find out the hard way. Do things right or leave it alone before you trash something.

quote Originally posted by Blue Shift: Little 10 cent tricks never have and never will work. 10 cent tricks do one thing very well though - costing you a 2000 dollar engine rebuild, which I'm sure you don't want to find out the hard way. Do things right or leave it alone before you trash something.

He has been told before, it won't matter if you tell him again... this is the game he plays

or if you want to advance the timing.. you can just adjust the distributor

quote Originally posted by Kohburn: or if you want to advance the timing.. you can just adjust the distributor

That's what I was thinking, but oh man, don't tell him that... I can totally see a reply post like this coming up: "Well I undid the bolt to the distribitor and turned it as far as it will go but its makeing this load knocking sound real loud. What's going on?"

quote Originally posted by Blue Shift: That's what I was thinking, but oh man, don't tell him that... I can totally see a reply post like this coming up: "Well I undid the bolt to the distribitor and turned it as far as it will go but its makeing this load knocking sound real loud. What's going on?"

LOL, agreed

here are some classic 88 forumla-isms:

https://www.fiero.nl/forum/Forum2/HTML/061300.html

https://www.fiero.nl/forum/Forum2/HTML/061583.html

https://www.fiero.nl/forum/Forum2/HTML/061891.html

[This message has been edited by ditch (edited 07-27-2005).]

quote Originally posted by Fastback 86: You're doing all this other stuff to shave off a few 10ths and you're still gonna run 87 octane and no additives? Fill it with Premium and throw in a bottle of octane booster. If you're this concerned about bringing your time down, theres no reason not to.

The engine is designed, tuned, and timed to run on 87.. Even putting race fuel in there isn't going to do anything to increase power if all else is the same. The only benefit is the injector cleaner in the premium fuel. Power will likely be lost. Higher octane gas has a higher activation energy; more energy is required to get it to go boom. There is not more energy content in the gasoline.
More on octane rating here: http://en.wikipedia.org/wiki/Octane_rating

didnt know about the injector cleaner isues, but havent had any probs yet., and i know better than to run high octane, its a waste of $$, and besides i only run non-ethonl/alcohol fuel, (cassy's 87 grade)(with acetone in every tank) and ive adjusted my timeing several times, the ecm is to smart to get a gain from it so its now back at stock. advancing timeing dont do a thing to the 2.8.

and about the track...!!!! rained out! didnt even get to run it!!, so im planing a next tuesday run , il let yous know about the resestors, my prognosis is im wasting my time. but who knows.

im still battling a cracked rear exaust manifold and non-working brakes. looking for cheap stainles steel brake lines(the ones between the braided lines and the calipers)